1. Field of the Invention
The present invention relates to an optical lens system for taking image, and more particularly to an optical lens system for taking image used in a mobile phone camera.
2. Description of the Prior Art
In recent years, with the popularity of camera mobile phone, the optical lens system for taking image has become thinner and thinner, and the sensor of a general digital camera is none other than CCD (Charge Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor). Due to advancement in semiconductor manufacturing, the pixel size of sensors has been reduced from 7.4 um of the early stage to the current 1.75 um. Therefore, there's increasing demand for thinner optical lenses.
In consideration of aberration correction, a conventional mobile phone's lens assembly usually consists of three lens elements, one of the typical structures is the Triplet type. However, when the length of the lens assembly is reduced from 5 mm to less than 3 mm, less space is available for the optical system, making it difficult to insert the three lens elements into the space of the optical system. Therefore, the lens elements must become thinner, causing poor uniformity if the lens is made from plastic injection molding.
The present invention mitigates and/or obviates the afore-described disadvantages.